Generally I agree that using this sort of thing to get a 'gotcha' moment out of it is a waste of time. The problem is that context doesn't help me understand what a person means when they say assualt rifle. I've had someone describe an assault rifle as anything that's specifically made to kill people.
For example, you mention the AK-47. I consider it to be a fully automatic, with selective fire, machine gun. You hold down the trigger, and the gun rapid fires until you remove your finger from the trigger, or you run out of ammunition.
Interestingly, and as far as I can tell, the author of the article did not make that. He assembled a semi-automatic-only version, based on the type that is available to gun enthusiasts. IE, not a full-auto machine gun.
But anyoo, just to be clear, you would term the following rifles to be assault rifles, correct?